<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        html,body {
            width: 100%;
            height: 100%;
            background-color: pink;
        }
        body {
            display: flex;
            flex-direction: row;
            justify-content: center;
            align-items: center;
        }
        .box {
            width: 200px;
            height: 200px;
            background-color: red;   
            position: relative;
            transform: rotate(45deg);        
            animation: boxhit 1s alternate infinite;
            box-shadow: 0 0 30px red;
        }
        .box::before {
            content: '';
            width: 200px;
            height: 100px;
            background-color: red;
            position: absolute;
            top: -99px;
            left: 0;
            border-radius: 100px 100px 0 0;
            box-shadow: 0 0 30px red;
        }
        .box::after {
            content: '';
            width: 100px;
            height: 200px;
            background-color: red;
            position: absolute;
            top: 0;
            left: -99px;
            border-radius: 100px 0 0 100px;
            box-shadow: 0 0 30px red;
        }
        @keyframes boxhit {
            0% {
                transform: rotate(45deg) scale(0.6);
            }
            100% {
                transform: rotate(45deg) scale(1.4);
            }
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>